So I needed to make a new one and i figured i'd take some pics and a quickie write-up on how to build a tester and do the check. (I did a search and couldn't find anything good, except people being confused what size couplers they need)

You'll need to go to Home Depot and get 2 parts and then stop by a tire shop and ask for a bigger size valve stem, which they will hook you up with for free.
Parts you need from Home Depot:

2" to 1.5" flexible drain rubber coupling ($4.47):

2" Threaded PVC plug ($0.55):

Everything together:

You will need to make a hole in the plug and insert the valve stem in there (use epoxy/jb weld for best results):

Then the plug will go into coupling like so (use epoxy/jb weld for best results):

Put a clamp on the coupling around the plug area (smaller clamp that comes with the coupling won't fit, it's too small, so you'll need to source a clamp from your garage or reuse one of the intake clamps. Or get one at home depot.) And here's the finished product:

Take off the intake filter and pipe and put the tester on the turbo inlet:

And get some air in there, using an air compressor or a compressed air can

(you can get it at home depot as well, and fill it up with air at gas stations). Pressurize it up to whatever PSI you can get, at least what you usually run, 21-25 or so. And listen for hissing. Use soapy water on hissing areas if you can't figure out where it's coming from.
But usual culprits are - IC piping couplers, turbo outlet pipe gasket, throttle body shaft gaskets (you can get replacement TB gaskets from WORKS and other sources) Make sure to keep your DV/BOV hooked up during the test (on UICP side) as it may be a leak source as well.
If you have an MBC - plug off the turbo line that goes in it (usually on the bottom of MBC) as MBC are supposed to let air vent, so it'll be doing just that during the test through a small hole unless you plug off that line (take off the line, put a screw in it).

P.S. You can also use your imagination at Home Depot and improve on this concept on your own! Also get some 5 minute epoxy if you don't have any in your garage and apply to where parts connect to avoid leaks.